The invention relates to a device for harvesting corn or similar cereals, especially to an attachment for combine harvesters or field choppers.
In the case of a known device of this type (DE-B-17 57 213; U.S. Pat. No. 2,870,593), the axes of rotation of the gathering rollers are aligned parallel to one another. The conicity of the working surfaces of the gathering rollers accordingly creates a passage gap, which decreases in width towards the rear base end of the gathering roller.
For a different, known device (DE-A-20 00 140, FR-A-1 268 615), the gathering rollers have cylindrical working surfaces. The axes of rotation of the gathering rollers diverge towards the front end of the gathering rollers, so that a passage gap, which decreases in width towards its rear end, is likewise formed by these means.
In the case of a furthermore known device (DE-C-39 18 362), the gathering rollers have cylindrical working surfaces and axes of rotation, which are mutually aligned in parallel and accordingly a passage gap, the width of which remains the same over its length. For comminuting the harvested stalks, a cutting device with, for example, a rotating cutting knife may be provided below the gathering rollers.
The invention is concerned with the problem of creating a harvesting device of the type mentioned above, which, while reducing the wear at the gathering rollers, realizes a gathering process, which treats the harvested material with particular care in the front region of the passage gap.
Because the axes of rotation of the gathering rollers are aligned so as to converge towards the front ends of the gathering rollers, the conicity of the gathering rollers can be selected freely from the point of view of specifying a desired speed of pulling the harvested material through the passage gap .and of increasing this speed towards the discharging end. while the desired configuration of the passage gap is retained. Accordingly, a relatively small diameter with a correspondingly low circumferential speed during the rotation while. working can be specified for the gathering rollers at the front inlet end of the passage gap, so that the action on the stalks of the harvested goods at the start of the drawing-through procedure sets in gently and the occurrence of slippage with the consequence of wear at the front ends of the gathering rollers is decreased. In coordination with the convergence angle of the axes of rotation, a conical angle can be specified for the gathering rollers and result in a relatively large increase in the diameter of the working circle of the gathering rollers, which is associated with a large increase in the circumferential speed of the working surface of the gathering rollers towards the discharging end of the passage gap. This increase in speed, which preferably is about 50%, permits an increase in the harvesting speed with gentle gathering or a shorter construction of the gathering rollers with retention of the harvesting speed.
Further details and effects arise out of the following description and the drawing, in which an example of the object of the invention is shown diagrammatically in greater detail.